1. Field of the Invention
The present invention relates to a control device of an electrical motor.
2. Description of the Related Art
In the prior art, it has been considered to be safe for a control device of an electric motor to forcibly cut off power to the motor in order to stop the motor. This is because the risk of runaway of the motor is not completely eliminated when the motor is stopped without cutting off the power by, for example, a slowdown control, in which the power is continuously supplied to the motor.
In the above forcible cutting-off of the power, the runaway of an electric power system may be avoided. However, the stopping time of the motor becomes longer because the motor is driven by inertia after the cutting-off of the power. Accordingly, the stopping distance of a movable part driven by the motor, in a device or a system, also becomes longer.